raven heat csi 85 a

[desrob]

works ok in dhw, but when ch is called for the boiler fires burns for approx 5 seconds then shuts down, then fires burns for 5 seconds then shuts down,it does this as long as you call for heat,the flow pipe is red hot and the return is barley warm,when the boiler is calling for heat and you run the hot tap for a long period when it switches back over it will work ok until temp is reached then it reverts back to fire, shut down, fire shut down etc the over heat stat and sensors are fine, burner pressure is ok ....?

 

[Billy Bob Bob]

check ch thermistor cold resistance,i think its 17 k cold but cant remember if that checks out pump could be ill

 

[desrob]

check ch thermistor cold resistance,i think its 17 k cold but cant remember if that checks out pump could be ill

i'm tending to lean towards a circulation problem the pump could be weak,

 

[desrob]

check ch thermistor cold resistance,i think its 17 k cold but cant remember if that checks out pump could be ill

i checked when hot and it was about 3k seems about right

 

[desrob]

still on with this ,not pump not stat ,pressures etc,starting to think about sensing probes,gas valve, in one of lighting sequence when it was lit i pulled a wire of modulator and the boiler ran perfect in low pressure mode until system temp was reached boiler knocked off and reverted back to miss behaving,also how would this boiler act when condensate is blocked were in lighting sequence would it effect it

 

[Billy Bob Bob]

still on with this ,not pump not stat ,pressures etc,starting to think about sensing probes,gas valve, in one of lighting sequence when it was lit i pulled a wire of modulator and the boiler ran perfect in low pressure mode until system temp was reached boiler knocked off and reverted back to miss behaving,also how would this boiler act when condensate is blocked were in lighting sequence would it effect it

strange it has a fly by wire linked to ignition on the condensate bottle should go strait to f/f

 

[desrob]

strange it has a fly by wire linked to ignition on the condensate bottle should go strait to f/f

were on conden is it wire ,because i can't see one

 

[Billy Bob Bob]

top of bottle it should be,it may not have anything though depending on its age,early ones did not have this set up

 

[desrob]

top of bottle it should be,it may not have anything though depending on its age,early ones did not have this set up

defo no wire ,,so it's not the conden blocked, i'm at a loss

 

[Billy Bob Bob]

it could be a blockage on the ch side i would start looking for a return filter,snapped iso valves or good old fashioned blocked pipes

 

[desrob]

it could be a blockage on the ch side i would start looking for a return filter,snapped iso valves or good old fashioned blocked pipes

just been to a ferrolli,i was getting same symptoms boiler would fire and knock off straight away ,every thing checked out,i checked the flue and the elbow was loose on top of boiler , i screwed it down,cleaned venturi and away it went..?

 

[Billy Bob Bob]

put your fga in the air intake see what you get normally though when you get vitiation dhw is the first to play up

 

[arran197]

It does sound like the condense problem, the old ones as Gas Man said, have the ignition lead that attaches to the condense trap. Connect these together (removing the trap connection) so they're just one lead. The newer ones are like this anyway. Check the primary flow thermistor on the right hand side for resistance. Sometimes the lead/plug are dodgy and die too.

Make sure you check your polarity too, a colleague had one that was doing something similar and the polarity was reversed. Pumps are rubbish and generally the hot water will still work if they're seized or dead.

 

[desrob]

yes the condensate is worrying me i can't see it condensing either because it's not getting to temp or secondary heat ex is blocked and just a thought i know it's a standard check but how does a boiler thats worked ok for years and no one been near it loose polarity

 

[desrob]

i was also surprised at the air pressure switch set up with only one tube connected to flue and the other taking it's air from sealed fan chamber,never came across this before

 

[Billy Bob Bob]

i was also surprised at the air pressure switch set up with only one tube connected to flue and the other taking it's air from sealed fan chamber,never came across this before

common on raven heats you will find it wont fire with the door off

 

[desrob]

common on raven heats you will find it wont fire with the door off

yes thats right

 

[arran197]

It doesn't have to be someone working on the boiler to reverse the polarity, could be the whole house. The boiler will still run the fan and the pump too. You are right, the combustion door has to be on for it to work. Even a few screws out the door will cause it to not fire. Which is another reason why fan's need replacing sooner than some other manufacturers. Have you tried blowing down the red tube to see if it'll fire up without requiring the fan?

If the secondary heat ex is blocked it will still fire up, but you will find you have a nice water feature after about 10 minutes running don the sight glass in the combustion door. Remove the garden hose looking condense pipe and blow up it to remove the blockage, but be prepared to swear a lot when it come to putting it back on.

I also had one the other day where the entire right hand side of injectors were blocked, causing the flames to be very small. If this is happening then it won't rectify. Might be worth pulling the rail off and each injector out and cleaning them up.

 

[desrob]

It doesn't have to be someone working on the boiler to reverse the polarity, could be the whole house. The boiler will still run the fan and the pump too. You are right, the combustion door has to be on for it to work. Even a few screws out the door will cause it to not fire. Which is another reason why fan's need replacing sooner than some other manufacturers. Have you tried blowing down the red tube to see if it'll fire up without requiring the fan?

If the secondary heat ex is blocked it will still fire up, but you will find you have a nice water feature after about 10 minutes running don the sight glass in the combustion door. Remove the garden hose looking condense pipe and blow up it to remove the blockage, but be prepared to swear a lot when it come to putting it back on.

I also had one the other day where the entire right hand side of injectors were blocked, causing the flames to be very small. If this is happening then it won't rectify. Might be worth pulling the rail off and each injector out and cleaning them up.

good advice...thanks

 

[desrob]

It doesn't have to be someone working on the boiler to reverse the polarity, could be the whole house. The boiler will still run the fan and the pump too. You are right, the combustion door has to be on for it to work. Even a few screws out the door will cause it to not fire. Which is another reason why fan's need replacing sooner than some other manufacturers. Have you tried blowing down the red tube to see if it'll fire up without requiring the fan?

If the secondary heat ex is blocked it will still fire up, but you will find you have a nice water feature after about 10 minutes running don the sight glass in the combustion door. Remove the garden hose looking condense pipe and blow up it to remove the blockage, but be prepared to swear a lot when it come to putting it back on.

I also had one the other day where the entire right hand side of injectors were blocked, causing the flames to be very small. If this is happening then it won't rectify. Might be worth pulling the rail off and each injector out and cleaning them up.

you mentioned blowing up the hose looking thing attached to condensate bottle, i did and it was solid meaning i could not blow up it ,is this correct

 

[desrob]

i'm still at a stand still with this, however ,i've removed the fan the conden heat ex and it was blocked , i cleaned it up and put every thing back,i thought i'd cracked it but no ,the boiler fires, burns for a second .i can hear what i think is the gas valve clicking and the boiler shuts off, and the sequence starts again,and this goes on and on ,the dhw works fine.